German document DE 10 2009 055 117 A1 discusses a master brake cylinder for an hydraulic vehicle brake system and a method for its operation. The master brake cylinder has a rod piston that may be designated as first piston and a tube-shaped second piston. The first piston is able to be displaced by a specifiable piston stroke through the second piston into a first pressure chamber of the master brake cylinder. A driving device developed on the second piston is supposed to have the effect that the first piston takes along the second piston after overcoming the predefined piston stroke. After overcoming the predefined piston stroke, the first piston and the second piston are supposed to be able to act in common upon the first pressure chamber of the master brake cylinder. In addition, using a floating piston, a second pressure chamber of the master brake cylinder is supposed to be able to be acted upon.